Australia’s trusted independent immunisation experts

Learn about the virus and the vaccines


COVID-19 is caused by the SARS-CoV-2 virus. There have been over 1 million confirmed cases of COVID-19 in Australia, including over 100,000 in children.1 Over 4,700 people have lost their lives, including six children.1 Most children who catch COVID-19 will get better; however, some children get so sick they need to go to hospital or be cared for by hospital staff in a 'hospital at home' program. Children with existing health issues are more likely to require hospitalisation. 

  • What is COVID-19?

    Coronavirus disease 19 (COVID-19) was found in humans in December 2019 and was declared a worldwide pandemic by the World Health Organization (WHO) in March 2020.

    It spreads easily and can be passed from person to person through coughing, sneezing, speaking, singing or breathing, or after touching contaminated surfaces or objects.2

    People usually start to feel unwell about 5–6 days after they get COVID-19.3 But this can range from 1 to 14 days.3 The most common signs of illness are headache, sore throat, cough, runny nose and fever.4

    A number of different versions or 'variants' of COVID-19 have emerged since the virus was first detected. These include Delta and Omicron. The vaccines available in Australia all offer protection against COVID-19 variants.

  • What are the risks of COVID-19?

    COVID-19 has killed over 12,000 children and adolescents around the world. Most children get better without needing medical help. However, some children have more serious disease and may need to go to hospital for treatments such as oxygen or ventilation (where a machine helps you breathe).5 

    Two rare but serious longer term problems can happen after infection. The first is a condition called multi-system inflammatory syndrome in children (MIS-C). This is also sometimes called paediatric inflammatory multisystem syndrome-temporally associated with SARS-CoV-2, or PIMS-TS. This occurs 2 to 6 weeks after COVID-19 infection.6 The disease causes multiple organs of the body to become inflamed. Organs may include the brain, heart, kidneys, lungs and digestive system.6 Children with this condition can become very sick and often need treatment in an intensive care unit.

    The second condition is often called ‘long COVID’.7 Some children with COVID-19 will still have symptoms of illness for many months after infection, including headache, fatigue, sleep problems and difficulty concentrating.7,8 The research is still evolving about 'long COVID' in children.

The COVID-19 vaccines

Australia is likely to get different COVID-19 vaccines over time. 

Two ‘mRNA vaccines’ are approved for children in Australia: the vaccine made by Pfizer/BioNTech (Comirnaty) and the vaccine made by Moderna (Spikevax). 

  • How do the COVID-19 vaccines work?

    The vaccines contain the genetic code for an important part of the COVID-19 virus called the spike protein. Spike proteins are found on the outside of the virus. Their job is to fuse to the outside of cells, so the virus can enter your cells and cause illness.

    When your child has the vaccine, their body reads this genetic code and trains their immune system to recognise the spike proteins and fight the virus. Within about two weeks of vaccination, their body will start making antibodies. After that, if they come into contact with the COVID-19 virus, these antibodies will attach themselves to the virus and help get rid of it. 

    Your child cannot catch COVID-19 from the vaccines because they don't contain the virus. They only contain the genetic code required to train your immune system to recognise and fight it.

  • How were the COVID-19 vaccines tested?

    Safety research is a key part of making vaccines. Vaccines are tested extensively before they are ready for use. Testing begins with research in a lab (test tubes), then animal studies and finally studies in humans (clinical trials), starting with adults and then children.

    Clinical trials involve testing the vaccine in volunteers, and run in three main phases:

    Phase 1 clinical trials usually involve a few dozen healthy volunteers. These trials focus on vaccine safety and finding out if the vaccine causes an immune response.

    Phase 2 clinical trials are bigger and have hundreds of volunteers. These trials test the immune response of the vaccine among a larger group of people, and assess whether it is safe, with acceptable side effects. 

    Phase 3 clinical trials involve many thousands of participants. These trials assess how effective the vaccine is at preventing people from getting the disease. Phase 3 trials can more thoroughly assess the vaccine for safety and side effects. In a Phase 3 trial, researchers usually compare people who received the vaccine with people who didn’t.  
    Typically, these phases happen one after the other. For the development of the COVID-19 vaccines, some of the phases overlapped. For example, Phase 3 studies were started as soon as early data from Phase 1 and 2 trials became available. This approach meant the COVID-19 vaccines could be developed quickly, making them available to save lives sooner.

  • What are the benefits of a COVID-19 vaccine for your child?

    Having the vaccine means your child will be less likely to catch COVID-19 and pass it on to others. If they’re vaccinated, they will be able to visit vulnerable or older family members more safely. Schools will also be safer.

    There is still a chance that your child will catch COVID-19, but if they do, they are likely to have no symptoms or mild symptoms.

    If you want to know more about the benefits of vaccination for yourself, an older teenager or another adult, we recommend that you use the Decision aid (16+ years): Should I get the COVID-19 vaccine?

  • What are the risks of a COVID-19 vaccine for your child?

    Most children and adolescents have mild symptoms for a day or two after a COVID-19 vaccine. This is completely normal and may include pain or tenderness at the injection site, headache, tiredness, chills, and muscle or joint pain.9 Serious side effects are very rare. We will provide more detail about the risks of vaccination side effects in the next steps of this decision aid. 

    If you want to know more about the risks of vaccination for yourself, an older teenager or another adult, we recommend that you use the COVID-19 decision aid (16+ years).

  • Do the vaccines work for different variants?

    Yes, the currently approved vaccines are effective against existing variants, including the Delta and Omicron variants. While the vaccines may not be as effective against some strains, they usually prevent severe illness.

+ References

  1. Australian Government Department of Health. Coronavirus (COVID-19) case numbers and statistics; Available from: Accessed February 2022.
  2. World Health Organization. Transmission of SARS-CoV-2: implications for infection prevention precautions. Scientific brief. [Internet.] Geneva: WHO; 9 July 2020. Available from:
  3. McAloon C, Collins Á, Hunt K, Barber A, Byrne AW, Butler F et al. Incubation period of COVID-19: a rapid systematic review and meta-analysis of observational research. BMJ Open. 2020;10(8). doi:
  4. Zoe COVID Study. What are the top 5 COVID symptoms? 2021. Available from: 
  5. Rothan HA, Byrareddy SN. The epidemiology and pathogenesis of coronavirus disease (COVID-19) outbreak. J Autoimmun. 2020;109. doi:  
  6. BMJ: Best Practice. Coronavirus disease 2019 (COVID-19). Available from: 
  7. Zimmermann P, Pittet LF, Curtis N. How Common is Long COVID in Children and Adolescents?, The Pediatric Infectious Disease Journal: December 2021 - Volume 40 - Issue 12 - p e482-e487 doi: 10.1097/INF.0000000000003328 
  8. Borch L, Holm M, Knudsen M et al. Long COVID symptoms and duration in SARS-CoV-2 positive children — a nationwide cohort study. European Journal of Pediatrics (2022).
  9. National Centre for Immunisation Research and Surveillance. AusVaxSafety. 2022. accessed February 2022.